The invention is concerned with a telephone answering system which includes a sensing circuit which responds to a ring signal on the telephone line to activate the system. When the system is so activated, a recorded announcement is transmitted over the telephone line to the calling party during a time interval (T.sub.1). A message recording tape is then activated in order that the calling party may record his message during a subsequent time interval (T.sub.2). In the system of the invention, the message recording equipment is voice actuated, so that the calling party is not limited to any particular prescribed time interval (T.sub.2) in which to record his message. So long as the calling party continues talking, the message is recorded up to the capabilities of the recording apparatus.
Voice actuated telephone answering systems are known to the art. However, problems have arisen in the prior art systems in that, for the most part, such systems were incapable of handling a situation in which the calling party hung up, without recording any message. When the calling party hangs up, usually a dial tone signal or a busy signal then appears on the telephone line, and the prior art voice actuated telephone answering systems had a tendency, instead of deactivating the recording process to continue to record the busy signal or the tone signal for the entire length of the recording tape, thereby wasting the entire unused portion of the tape.
In an attempt to solve the problem, telephone answering systems have been conceived in the past which, for example, respond to potential changes on the line when the calling party hangs up, in order to deactivate the telephone answering systems. However, such systems are not effective to deactivate themselves in the event the calling party hangs up during the announcement interval (T.sub.1), when the system is not responding to incoming signals but is transmitting an announcement over the telephone line to the calling party.
Other systems have been conceived in the past which respond, for example, to a silence or a dial tone on the telephone line, following a hang-up by the calling party to deactivate themselves. However, many telephone systems automatically produce a busy signal on the telephone line a predetermined time interval after the calling party has hung up. Accordingly, a situation can arise where the calling party hangs up during the announcement interval (T.sub.1) of a telephone answering system, for the system to encounter a busy signal on the telephone line when it switches itself to the message recording mode (T.sub.2). Most prior art voice operated telephone answering systems are incapable of distinguishing the received busy signal from normal voice signals, and this results in the busy signal being recorded during the remaining length of the message recording tape, and thereby wasting the message tape.
The voice operated telephone answering system of the present invention is constructed so that when the system enters the message recording mode (T.sub.2), at the end of the announcement interval (T.sub.1), it will remain activated only so long as the system actually receives a human voice. Should the calling party hang up at any time during the announcement interval (T.sub.1), or during the message interval (T.sub.2), so that a silence, a dial tone, or a busy signal occurs on the telephone line at the beginning or during the message interval (T.sub.2), the system of the invention will deactivate itself thereby stopping the message tape.